Shell beans if using shelling beans. Remove the kernels from the ears of corn and put in a bowl.
In a small saucepan of boiling salted water cook beans over moderate heat, stirring occasionally, until just tender, about 5 minutes. In a sieve drain beans and rinse under cold running water to stop cooking. Set aside.
In a skillet cook bacon over moderate heat until crisp. Drain bacon on paper towels and crumble. Pour off all but 1 tablespoon of the bacon fat from skillet. Add oil to bacon fat in skillet and cook onion over moderate heat, stirring, until just softened. Add garlic and cook for 1 minute more. Add tomatoes, corn kernels, and vinegar and cook, stirring, until tomatoes just begin to lose their shape. Remove skillet from heat and gently stir in cooked beans and half the bacon. Cool succotash to room temperature and gently stir in basil and arugula, and salt, pepper, and additional sherry vinegar to taste. Toss with croutons and sprinkle with remaining bacon before serving.